盐类矿物结晶水H和O同位素研究的科学意义与测定方法

为建立精确测定盐类矿物结晶水H和O同位素组成方法，进一步丰富自然界矿物流体H和O同位素分馏机理，并为发展和推广盐类矿物结晶水H和O同位素地球化学应用研究打基础，在全面论述盐类矿物结晶水H和O同位素研究的科学意义及前人研究工作的基础上，以蒸发岩沉积序列中分布普遍、含结晶水量大的石膏(早期沉积阶段矿物)与光卤石(晚期沉积阶段矿物)为代表性矿物，通过实验室等温蒸发条件实验及天然矿物分析，建立了盐类矿物结晶水分离提取及测试的关键技术方法。实验结果表明，采用当前通用的基于MAT253质谱系统连续流进样，可以准确、快速地测定自然界盐类矿物结晶水H和O同位素组成。     

伊宁板块南北缘沉积（变质）岩钕同位素组成及大地构造 …

分析了伊宁板块南北缘的沉积（变质）岩钕同位素组成,利用沉积岩中钕同位素模式年龄探讨塔里木板块、伊宁板块和准葛尔板块之间的关系。伊宁板块北缘阿拉套山脉西部沉积物物源区年龄的１．９Ｇａ。东部沉积岩钕模式年龄０．９￣１．４Ｇａ,表明伊宁板块与准葛尔板块碰撞造山作用,幔源物质的加入有关。伊宁板块南缘的志留系沉积物来自约２．５Ｇａ的物源区。     

伊宁板块南北缘沉积(变质)岩钕同位素组成及大地构造意义

分析了伊宁板块南北缘的沉积（变质）岩钕同位素组成,利用沉积岩中钕同位素模式年龄探讨塔里木板块、伊宁板块和准葛尔板块之间的关系．伊宁板块北缘阿拉套山脉西部沉积物物源区年龄约１．９Ｇａ东部沉积岩钕模式年龄０．９－１．４Ｇａ,表明伊宁板块与准葛尔板块碰撞造山作用,幔源物质的加入有关．伊宁板块南缘的志留系沉积物来自约２．５Ｇａ的物源区．     

漠滨金矿稳定同位素研究

本文通过对漠滨金矿的硫、氢、氧及铅同位素的测定数据,对该金矿的同位素组成、空间分布、地质计温、流体来源及模式年龄等方面进行了讨论,并结合其他方面的资料和研究结果,探讨了该矿床的成因。     

氧化干馏法从铜精矿焙烧烟道灰中提取锇的研究

钼(铜)精矿焙烧烟道灰是钼(铜)精矿在氧化沸腾炉焙烧过程中产生的含有丰富的有色金属和稀贵金属的高温烟尘,是提取铂族元素的重要资源.以烟道灰为原料,采用氧化干馏法分离提取锇.先用常温湿法浸取烟道灰中的锌、铜、镍和铅等有色金属,烘干烟道灰浸渣,将烟道灰干渣与氧化剂混合均匀后进行氧化干馏,从而回收锇.结果表明:将烟道灰干浸渣和其质量8%的复合氧化剂,在140℃下氧化干馏30 min,用20%NaOH和0.5%C_2H_5OH的混合溶液进行三级吸收OsO_4,锇的回收率不低于85%.     

浙江黄双岭萤石矿的同位素研究

文章公布了浙江黄双岭萤石矿的氢、硫、锶和铅同位素分析结果,讨论了成矿溶液和成矿物质来源,估计黄双岭萤石矿的成矿年龄大约为107Ma。     

恒山－五台地区同位素年代学与地质事件演化格架的认识

近10年在恒山和五台地区所获得的大量同位素年代学资料,统计发现恒山杂岩的同位素年龄峰值比五台杂岩大致要年轻20 Ma, 这与恒山－五台地区为岛弧根带－岛弧关系的推论相符合。综合各种不同的同位素测年结果按不同的地质体,进行了图解分析,将恒山－五台地区早前寒武纪的地质演化划分为3个大的阶段：2.70～2.60 Ga,早期演化（洋壳形成？）;2.55～2.52 Ga(?,最晚不晚于2.45 Ga),东西陆块俯冲碰撞阶段;2.50～1.75 Ga,早期盖层演化阶段。最后一个阶段有可以根据不同时段内研究区主要事件的不同,将2.50～1.75 Ga的演化分为5个时期。1）2.50～2.30 Ga表现为间歇性大陆溢流玄武岩的活动期;2）2.30～2.20 Ga华北较稳定沉降期,基本以接受沉积为主;3）2.20～2.10 Ga,构造活化期,五台地区主要有伸展非造山花岗岩（大洼梁花岗岩）的形成;4）2.10～1.85Ga阶段,地幔柱活动期？ 5）1.86～1.75 Ga,大规模基性岩墙形成期陆块裂解。     

深海泥的矿物组成及其物化性能研究

采用化学分析、X射线衍射、差热和热重分析、粒度与比表面积分析等技术、方法对5个我国南海深海泥样品进行了研究.结果表明,不同区域的深海泥中,其矿物组成有显著的差异,其中粘土矿物、石英、碳酸盐为主要的结晶相矿物;同时,非晶质粘土矿物广泛发育.深海泥中的矿物质具有粒径小、比表面积大、粘土矿物结晶程度差等特点,因此具有较好的活性.深海泥将是一种巨大的潜在非金属矿产资源.     

寿山石矿物组成及其分类的XRD研究

采用X射线衍射方法研究数十个寿山石样品的矿物组成。结果表明,这些寿山石样品可分为九类,其颜色、透明度因矿物、组成的差异而有所不同。说明影响寿山石的品质的因素是非常复杂的。     

美国Wallapai矿区Mineral Park斑岩型矿床早期矿脉中硬石膏的氧同位素组成

本文报道了美国亚利桑那Wallapai矿区Mineral Park斑岩型矿床早期矿脉(AM和AC)中硬石膏的氧同位素组成,依据包体均一温度及硫同位素温度计算成矿溶液的δ~(12)O值(纯水),运用同位素分馏理论讨论AM和AC矿脉成矿溶液的来源和演化。     

Chondritic osmium isotopic composition of late Archean convecting upper mantle：Evidence from Zunhua podiform chromitites,Hebei, North China

The Os isotopic composition and evolution of con-vecting upper mantle (CUM) are an important and diffi-cult scientific issue related to the distributions of PGEs inearth’s interior and the accretion history of the earth. De-termination of 187Os/188Os of modern CUM has been at-tempted via analyses of abyssal peridotites, mid-oceanridge basalts (MORB), MORB glasses and sulfides. Abyssal peridotites, which are mantle samples re-covered from the ocean ridges, represent the upperm…     

Os isotopic compositions of a cobalt-rich ferromanganese crust profile in Central Pacific

Cobalt-rich ferromanganese crusts occur throughout the global ocean on seamounts, ridges, and plateaus where currents have kept the rocks swept clean of sediments for millions of years. Crusts are important as a potential re-source for primarily cobalt, but also for titanium, nickel, REE, PGE, and other elements. Most Co-rich crusts pre-cipitate at water depths of about 1000-3000 m, and are easy to be exploited. Besides the high cobalt contents compared to abyssal Fe-Mn nodules, exploitati…     

Re-Os isotopic system and formation age of subcontinental lithosphere mantle

The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. It is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, etc., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.     

Determination of carbon isotopic composition of individual light hydrocarbons evolved from pyrolysis of source rocks by using GC-IRMS

The carbon isotopic composition of individual light hydrocarbons generated from source rocks that had been pyrolysed in vacuum glass tube were determined by using the GC-IRMS techniques. The results indicate that abundant CO2 in the pyrolysates has a remarkable effect on the determination of CH4δ13C. Running cryogenically with an initial temperature of -40℃can effectively eliminate the effect. In addition, it conduces to measuring the δ13C of C2+ hydrocarbons by increasing the injection volume and/or absorbing CO2 with the solution of sodium hydroxide.The above measures will help to get the carbon isotopic composition of C1-C7 components, which is of great significance for gas/source rock correlation and for study on the genesis of natural gas.     

Nd isotopic disequilibrium between minerals and Rb-Sr age of the secondary phengite in eclogite from the Yangkou area, Qingdao, eastern China

There are two generations of white micas in retrograded coesite-bearing eclogite from the Yangkou area near Qingdao, eastern China. The secondary phengite developed along the folliations in eclogite is the majority of the white micas. Nd and Sr isotopic disequilibriums between garnet and retrograded omphacite as well as secondary phengite have been observed. Consequently, the Rb-Sr ages ((193 ± 4) Ma―(195 ± 4) Ma) given by the tie lines of the secondary phengite + garnet or whole rock may predate the formation time of the phengite. The Rb-Sr age of (183 ± 4) Ma given by the secondary phengite + retrograde omphacite is much closer to the formation time of the phengite indicating the retrograde age of eclogite instead of a cooling age of eclogite at 500℃.     

Main pollution sources of central Arctic revealed by lead and its isotopic ratios recorded in snow

The spatial distribution and environmental significance of Pb and its stable isotope ratios in central Arctic snow are discussed. The shear zone is a dividing line. The concentration of Pb in the south section is higher than that of the north section, and in the shear zone it is close to that of sea salt. Anthropogenic Pb by calculation is larger than 99%. Its main sources are polluted air masses origi nation from Europe and the midpart of Russia, as well as the western North America and far east Russia. This is also conformed by 206Pb/ 207Pb.     

Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years

An oxygen isotope record of a stalagmite from Huanglong Cave in the eastern Qinghai-Tibet Plateau dated with 230Th and 210Pb methods provides variations of the Asian monsoon with an average resolu-tion of 1 year over the past 50 years. This study shows that the δ18O of dripwater in the cave represents the annual mean δ18O of local meteoric precipitation and the stalagmites were deposited in isotopic equilibrium. A comparison of the stalagmite δ18O record with instrumentally meteorological data indi-cates that shifts of the δ18O are largely controlled by the amount effect of meteoric precipitation con-veyed through the southwest monsoon(the Indian monsoon) and less affected by temperature. Therefore,the variations of δ18O record reflect the changes in monsoon precipitation on inter-annual time scales under the influence of the southwest monsoon. Like many other stalagmite δ18O records in the Asian monsoon regions,the δ18O record of the stalagmite from Huanglong Cave also reveals a gradually enriched trend during the past 50 years,i.e. relatively enriched in 18O. This trend may indicate the decline of the Asian monsoon intensity which is consistent with the decrease of monsoon indices. The weakening of the modern Asian monsoon well matched with the temperature changes in strato-sphere,which may illustrate that the weakening of the monsoon mainly results from the lowering of solar radiation.     

Hydrogen isotopic compositions and their environmental significance for individual n-alkanes in typical plants from land in China

Hydrogen isotopes of n-alkanes in grasses, tree leaves and reeds from six regions with latitudes of 20° to 39°N in China are measured by GC-TC-IRMS analytical technique in order to understand their hy- drogen isotopic compositions and environmental significance. The results show that a difference in δ D values (from -42.1‰ to -66.6‰) of n-alkanes exists among the same kinds of plants from various re- gions. Hydrogen isotopic compositions of most even carbon numbered n-alkanes in every plant are slightly hea...